Treating Spa after kids use? Is this too much?

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Kpax755

Active member
May 11, 2020
34
Columbus, OH
Hello, I have been following the helpful advice of the folks on this site and also doing the dichlor/bleach method. I have been using 10% bleach after use, but I think i am not using quite enough as I had some cloudiness and doing some SLAM now to clear. We regularly have 3 or 4 adults and 3 kids in the spa daily. Some of them are still in diapers, so lots of Crud in the water. Plus a dog dropping a dirty tennis ball.

From my research it sounds like I should bet on 7ppm FC per bather per hour. If we are all in the spa for an hour, does this mean I need around 42ppm FC added, which for my spa size (430 gallon + ozone) would be around 24oz of 10% bleach after use? Seems like a LOT so wanted to just ask...(I know bather load is HIGH!)

I am also doing around 6-9oz per day regardless of use and balancing as needed.

Any comments appreciated!
 
Heavy bather load indeed. Kids in diapers are tough to keep up with, and if they have a fecal incident it is imperative that you maintain your FREE chlorine at 40ppm for 8.5 hours. This requires frequent testing as your free chlorine will drop as it interacts with contaminants. I usually raise to 60ppm to avoid frequent testing and chlorine additions. You will then need sodium thiosulfate (chlorine neutralizer) or ozone to reduce chlorine to useable range

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Thanks @RDspaguy !

So I was talking to my local dealer service tech, and he was pretty against using liquid chlorine and said to only use Dichlor after use.

My question is how do I keep up with bather demand with just Dichlor? It seems like since we have 4-6 people using ours daily, I would hit my CYA level limit in just a few days!

Is it safe to use the liquid chlorine or why is he so against it? I don't think he cares if they sell me chemicals or not.
 
Most are not familiar with the "correct" way to safely and properly use liquid chlorine.

You are correct, you wouldn't be able to keep up with FC demand, and I would strongly suggest not to try with dichlor...

Yes it is! Hundreds use it here, season after season and have longevity of equip and no health issues!
 
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Kpax755 said:
Hello, I have been following the helpful advice of the folks on this site and also doing the dichlor/bleach method. I have been using 10% bleach after use, but I think i am not using quite enough as I had some cloudiness and doing some SLAM now to clear. We regularly have 3 or 4 adults and 3 kids in the spa daily. Some of them are still in diapers, so lots of Crud in the water. Plus a dog dropping a dirty tennis ball.

From my research it sounds like I should bet on 7ppm FC per bather per hour. If we are all in the spa for an hour, does this mean I need around 42ppm FC added, which for my spa size (430 gallon + ozone) would be around 24oz of 10% bleach after use? Seems like a LOT so wanted to just ask...(I know bather load is HIGH!)

I am also doing around 6-9oz per day regardless of use and balancing as needed.

Any comments appreciated!
Click to expand...

"Also, the 7 ppm FC in 350 gallons per person per hour of soaking guideline (at 104F) isn't in the Pool School either. This translates into amounts that are independent of spa volume of 3-1/2 teaspoons of Dichlor or 5 fluid ounces of 6% bleach or 7 teaspoons of MPS non-chlorine shock. These are conservative amounts of chlorine needed to oxidize bather waste (mostly ammonia/urea from sweat/urine). The biggest mistake most spa users make is not using enough oxidizer in their spas, especially if such spas are more heavily used. "

The key words are "independent of spa volume". The 7 ppm Richard mentioned was for his example of a 350 gal spa. The average sanitizer amount needed is a "constant" per person hour. These values are :

  • Chlorine usage is 5oz 6% bleach (148ml) / person hour, 17g dichlor, 34.7 ml 43% MPS or 26.98ml 55% MPS

So, regardless as to your spa size, add the above to oxidize the bather waste.
 
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When I started in this business bromine is what was used in a spa. Period. As bromine is unaffected by cya, the preferred shock was dichlor, due to it's relatively neutral ph and high oxidation potential. And you did not even test cya in a bromine spa. This is not the case for chlorine spas, obviously, but many in the industry still hold to the old ways since that is what they were told by the old guys (like me) who trained them. It was not until I began to maintain pools as well that I understood the difference, and that was many years after I started. Most spa techs are not pool techs, and vice-versa.
Here is a great article from Taylor explaining the differences in various chlorine and bromine types.
 
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Thanks everyone! He specifically used the words "liquid CL will eat your spa up" regarding the liquid chlorine, I am assuming he means people putting too much in or something and hurting the equipment/seals?


tillmac62 said:
Chlorine usage is 5oz 6% bleach (148ml) / person hour, 17g dichlor, 34.7 ml 43% MPS or 26.98ml 55% MPS
Click to expand...

Appreciate that! I have come up with a similar calculation using the above and pool math, and it looks like I need about 4 oz of 10% sodium hypo / person hour (430 gallons).

So for example, if 4 people soak for 1 hour, I need to add 16 oz of 10% bleach to compensate for their bather waste? Before people get in, I usually add around 4 oz.
 
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Kpax755 said:
Thanks everyone! He specifically used the words "liquid CL will eat your spa up" regarding the liquid chlorine, I am assuming he means people putting too much in or something and hurting the equipment/seals?




Appreciate that! I have come up with a similar calculation using the above and pool math, and it looks like I need about 4 oz of 10% sodium hypo / person hour (430 gallons).

So for example, if 4 people soak for 1 hour, I need to add 16 oz of 10% bleach to compensate for their bather waste? Before people get in, I usually add around 4 oz.
Click to expand...
You got it, almost. You need 3oz per person hour of 10% .
 
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Liquid chlorine, as you know, is high ph. Used in the concentrations you will need in your spa it will raise your ph drastically. High ph, as you know, causes scale. Scale is death to a spa electric heater as it accumulates on the element and causes it to burn out. The rubber gaskets behind each jet also respond poorly to high ph and are very expensive to repair.
So, in that sense, liquid chlorine will eat up your spa. If you do not maintain your ph with OCD like regularity.
 
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